Juventus, Barcelona and Real Madrid have not renounced the ESL, which claimed Uefa and Fifa broke European Union competition law by blocking its creation.
“When I was president of the ECA (European Clubs Association) and of the Uefa executive committee, the analysis was evident,” said Agnelli.
“There was no club sustainability, a vertical polarisation of interest towards only two leagues, access to very risky financial instruments and fan disaffection.
“The proposal at the time was the creation of a league system with access different from the classic ones. This proposal was made in 2019.
“If I personally wanted to maintain my privileged situation, I would not have taken the decisions of April 2021.”
In a report released by the European Court of Justice in December, advocate general Athanasios Rantos said Uefa and Fifa’s actions were “compatible with EU competition law”.
A final ruling will be made by a 15-member Grand Chamber next spring.
Agnelli said: “The hope is that the European Court of Justice recognises professional sport as an industry, since the turnover of football is 55 billion euros (£48bn).
“I thank Real Madrid and Barcelona who, together with Juventus, had the courage to face the threats from Uefa.”
Agnelli was speaking at a Juventus shareholders meeting on Wednesday where a new board of directors was approved, with Gianluca Ferrero replacing him as chairman.
The Italian giants won nine Serie A titles in a row during Agnelli’s 13-year tenure, but finished fourth last season and made a 254m euro (£220m) loss – a record in Italy.
Juventus, who are listed on the Italian stock exchange, are being investigated for allegations of presenting false accounting information to investors and producing invoices for non-existent transactions.
Agnelli and vice-president Pavel Nedved, who has also stepped down, are among those under investigation.
The club have denied any wrongdoing.
Other clubs are also the subject of a parallel investigation launched by the Italian Football Federation (FIGC) in October.